The satellite collision that destroyed two U.S. and Russian orbiters on January 10, 2009, added more than 500 bits of debris to the roughly 18,000 pieces of known space junk orbiting Earth (shown in an artist's conception).

The collision occurred about 491 miles (790 kilometers) over Siberia, putting most of the debris well above the path of the International Space Station, which circles about 220 miles (354 kilometers) above the Earth.
Although it will take a few days to get a complete picture of the debris field, NASA officials calculate that the crash would have thrown only a very small number of objects in the space station's direction.

"There are actually debris from this event which we believe are going through the space station's altitude already," NASA's Nicholas Johnson told CBS News, but the risk to the station is very small.